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Pressure Relief Valve (PRV): Definition, Types, Working, Location, Sizing, Codes and Standards

Written by Anup Kumar Dey in Instrumentation,Mechanical,Pipeline,Piping Design Basics,Piping Interface,Process

A pressure relief valve is used to release excess pressure from a system during overpressure situations thus avoiding catastrophic failure. So, a Pressure relief valve is an important process safety device and is widely used in the chemical, petrochemical, power, and oil and gas industries. The pressure relief valve (PRV) is designed to open at a predefined set pressure. So whenever the system pressure exceeds the set pressure, the PRV pops and releases the overpressure and when the excess pressure is removed the PRV closes again. The main advantages of installing a pressure relief valve in a system are:

  • They vent the fluid to safeguard the system from overpressure.
  • They reclose and prevent loss of fluid when system pressure returns back to acceptable.
  • Installation of the PRV system minimizes damage to system components.
  • They are reliable and versatile

What are Relief Events?

Relief events are obligatory events that prevent efficiency or performance and increase cost but must be met considering the safety of the operating plant. Examples of potential relief events are

  • External fire
  • Flow from a high-pressure source
  • Heat input from associated equipment/ external source
  • Pumps and compressors or other equipment failures.
  • Failure of Cooling Medium
  • Ambient heat transfer
  • Failure of the Control system
  • Liquid expansion in pipes and surge
  • Blocked discharge, Gas blowby
  • Failure of the Condenser system
  • Chemical reactions
  • Operating error
  • Closed Outlets
  • The entrance of Volatile Fluid

Potential Lines of Defense against Relief Events

To act against the above-mentioned potential relief events the following defense methods are followed.

  • Inherently Safe Design
  • Low-pressure processes
  • Passive Control
  • Overdesign of process equipment
  • Active Control
  • Install Relief Systems

What is a Relief System?

A relief system is an emergency system used to safeguard plants during relief events by reducing pressure or discharging gas during abnormal situations. The relief system consists of

  • A relief device, and
  • Associated lines and process equipment to safely handle the material ejected

Why Use a Relief System?

Installing relief systems in operating plants is a must from the process and technical safety points as

  • Inherently Safe Design simply can’t eliminate every pressure hazard
  • Passive designs can be exceedingly expensive and cumbersome
  • Relief systems work!

Code Requirements for relief system design

General Code requirements include:

  • ASME Boiler & Pressure Vessel Codes
  • ASME B31.3 / Petroleum Refinery Piping
  • ASME B16.5 / Flanges & Flanged Fittings

Relieving pressure shall not exceed MAWP (accumulation) by more than:

  • 3% for fired and unfired steam boilers
  • 10% for vessels equipped with a single pressure relief device
  • 16% for vessels equipped with multiple pressure relief devices
  • 21% for fire contingency

Locating Pressure Relief Valves

The location of Pressure Relief valves is decided by Process Engineers. They mention the PRV requirements in the P&ID. Below are the General guidelines on where relief devices are required, although there are likely to be other special cases in any process.

  • All vessels
  • Blocked in sections of cool liquid lines that are exposed to heat
  • Discharge sides of positive displacement pumps, compressors, and turbines
  • Vessel steam jackets
  • Low-pressure storage tanks require both vacuum and pressure relief devices since tanks are typically not designed for full vacuum.
  • Wherever formal hazard identification procedures such as Hazard and Operability (HAZOP), Process Hazard Analysis (PHA) indicates
  • Piping systems where overpressure can arise due to process control failure.

Types of Pressure Relief Valves

Conventionally Pressure relief valves are categorized into the following three groups:

  • Relief Valve
    • Adjustable
    • Electronic
  • Safety Valve
    • Low Lift
    • High Lift
    • Full Lift
  • Safety Relief Valve
    • Conventional spring-loaded safety relief valve pilot-operated
    • relief valve
    • Balanced-bellows type relief valve
    • Power actuated
    • Temperature and Pressure actuated relief valve

The above-mentioned pressure relief valve types are produced in graphical form in Fig. 1 below

Types of Pressure Relief Valves
Fig. 1: Types of Pressure Relief Valves

Relief valves are spring-loaded and characterized by gradual opening and closing. They are actuated by the upstream pressure and are suitable for incompressible fluids. Adjustable relief valves allow the pressure setting adjustment through the outlet port. Electronic relief valves offer zero leakage with electric controls to monitor and regulate the system pressure.

On the other hand, safety valves are used for compressible fluids (gas and vapors) and are characterized by the rapid action of opening and closing. Safety valves are widely used in steam plants for boiler overpressure protection. They are classified into three groups based on the amount of travel or lift during the pop-up. Low-lift safety valves have a small capacity and the valve lifts 1/24th of the bore diameter. High-lift safety valves travel 1/12th of the bore diameter. Whereas Full-lift safety valves travel at least 1/4th of the bore diameter and are best suited for steam services.

The safety relief valve can be used for gas or liquid service depending on the application. They have the characteristic of both rapid and gradual opening.

Conventional Pressure Relief Valve

Spring-loaded conventional pressure relief valves are best suited for applications where excessive back pressure is absent. The back-pressure directly affects the operational characteristics of these PRVs. Refer to Fig. 2 which represents a conventional safety relief valve with its basic elements.

Conventional type Pressure Relief Valve
Fig. 2: Conventional type Pressure Relief Valve

There are three basic components of a conventional pressure relief valve

  • An inlet nozzle to be connected to the system requiring protection.
  • A movable disk for fluid flow control, and
  • A spring for controlling the disk position.

While designing a conventional pressure relief valve, consideration of seat leakage to be checked as leakage means continuous loss of system fluid and the valve seating surface can be damaged. Depending on the seating material, conventional pressure relief valves are classified into the following two types:

  • Metal-seated valves, and
  • Soft-seated valve

Pros & Cons of Conventional Pressure Relief Valves

Advantages

  • Most reliable type if properly sized and operated
  • Versatile — can be used in many services

Disadvantages

  • Relieving pressure affected by back pressure
  • Susceptible to chatter if built-up back pressure is too high

Balanced Bellows Type Pressure Relief valve

To reduce the effects of backpressure, spring-loaded balanced bellows pressure relief valves (Fig. 3) are developed. The PRV design incorporates a bellow that offsets the effect of back pressure. The bellow isolates the spring, bonnet, and guiding surfaces from direct contact with the process fluid.

Typically when back pressure is variable and exceeds 10% of the set pressure, a balanced-bellows type pressure relief valve is used.

Balanced Bellow type Pressure relief valve
Fig. 3: Bonnet Bellow type PRV

Pros & Cons of Balanced Bellows type Pressure Relief Valve

Advantages

  • Relieving pressure not affected by back pressure
  • Can handle higher built-up backpressure
  • Protects spring from corrosion
  • Possess good temperature and chemical properties

Disadvantages

  • Bellows are susceptible to fatigue/rupture
  • May release flammables/toxics into the atmosphere
  • Requires a separate venting system

There are two types of balanced bellows safety relief valves:

  • Balanced bellows
  • Balanced bellows with auxiliary balancing piston

Pilot-operated Pressure Relief Valves

A pilot-operated safety relief valve is a pressure relief valve where a self-actuated auxiliary pressure relief controls the pressure-relieving. The opening or closing of the relief valve is governed by the pressure of the flowing medium. A pilot is used to sense the process pressure and to pressurize or vent the dome pressure chamber, which controls the valve opening or closing. Three main components consist of a pilot-operated pressure relief valve (Fig. 4)

  • the main valve,
  • a floating, unbalanced piston assembly, and
  • an external pilot.
Pilot-Operated Pressure Relief Valve
Fig. 4: Pilot-Operated Pressure Relief Valve

The pressure on the top side of the main valve’s unbalanced moving chamber is controlled by the pilot. Generally, a resilient seat is attached to the lower end.

Advantages of Pilot-Operated Pressure Relief Valve

The main advantages of pilot-operated safety relief valves are:

  • The set pressure is unaffected by the valve backpressure.
  • As the system operating pressure decides the opening of the relief valve, the system can be operated at maximum working pressure.
  • Economical as compared to other types.
  • Less susceptibility to chatter.

Pilot-operated Pressure relief valves can be classified based on various parameters as mentioned shown below:

  • Depending on the type of moving members
    • A piston-type.
    • A diaphragm-type.
  • Based on the type of pilots
    • A pop-action pilot
    • A modulating-action pilot
  • Based on the flow of pilots
    • A flowing-type pilot.
    • A non-flowing-type pilot

Power Actuated Pressure Relief Valve

Power-actuated pressure relief valves (Fig. 5) are controlled by a device requiring an external power source. Energy sources like water, electricity, or steam control the opening and closing of the pressure relief valve. They are mostly used for forced-flow steam generators with no fixed steam or waterline and in nuclear power plants.

Temperature Pressure actuated Pressure Relief Valves

A temperature and pressure-actuated pressure relief valve (also known as T&P safety relief valve-Fig. 5) is actuated by the temperature or pressure of the inlet side of the relief valve. The valve consists of two primary controlling elements, a spring, and a thermal probe. They serve dual purposes.

  • Prevention of temperature rise above specified and
  • Prevention of over-pressure from rising above a specified value.

They are mostly used for vessels, tanks, and heaters carrying hot fluids.

Power and Temperature Actuated Safety Relief Valve
Fig. 5: Power and Temperature Actuated Safety Relief Valve

Vacuum Relief Valve

A Vacuum Relief Valve is designed to prevent an excessive internal vacuum by admitting fluid. Once the normal condition is restored, they reclose and prevent further fluid flow.

When to Use a Spring-Operated Pressure Relief Valve

  • Losing entire contents is unacceptable
    • Fluids above the normal boiling point
    • Toxic fluids
  • Need to avoid failing low
  • Return to normal operations quickly
  • Withstand process pressure changes, including vacuum

Pressure Relief Valve Accessories

A number of pressure relief valve accessories help the valve in its operations to achieve the intended use. They are:

  • Test gags hold the safety valve closed during the hydrostatic test.
  • Lifting mechanisms to lift the valve disk. Available in three types
    • plain lever,
    • packaged lever, and
    • air-operated lifting devices.
  • Bolted caps are available for standard pressure relief valves in addition to the screwed caps.
  • Valve position indicators for remote indication of the PRV opening

Working of a Pressure Relief Valve

For a spring-loaded pressure relief valve, the spring force holds the disk in position keeping the valve in a closed position. When the pressure of the line exceeds the set pressure, the disk starts to lift allowing the fluid to flow through the outlet and release pressure. With a further increase in inlet pressure, the disk lifts further. When the disk has traveled to its designed value, the valve is fully open and the system pressure is released.
Once the overpressure inside the system falls below the spring force the spring pushes back the disk in positive to close the valve preventing further release of fluid.

For pilot-operated pressure relief valves, the inlet pressure is directed to a small safety valve that acts on top of the piston. As the top area of the piston is designed greater than the bottom area under fluid contact, the pressure on top is higher which pushes the piston to close the relief valve. When the inlet pressure rises above the set pressure, a net upward force acts on the piston forcing the piston to pop up and release the pressure.

Codes and Standards for Pressure Relief Valve

Pressure relief valves are governed by codes and standards. The most widely used pressure relief valve codes and standards are:

  • ASME BPVC (Sec I, Sec III, Sec IV and Sec VIII)
  • ISO 4126
  • API 520
  • API 521
  • API 526
  • API 527
  • PED 97/23/EC
  • EN4126
  • JIS B 8210 (Japan)
  • KS B 6216 (Korea)
  • SAA AS 1271 (Australia)

Relief Valves – Pressure Terminologies

Let us understand some additional basic terms which are widely used in relation to relief valves.

The set pressure is the pressure at which the relief valve starts to open. It is normally the same as design pressure and is measured at the valve inlet. For spring-operated relief valves small amount of leakage (simmer) starts at 92-95% of the set pressure.

Overpressure is the pressure increase over the set pressure of a pressure relief device, during discharge and is usually expressed as a percentage of the set pressure (normally overpressure is set to pressure +10%) Relief valve achieves its full discharge capacity at overpressure

Accumulation is the pressure increase over the DP/ MAWP of equipment during discharge through the protecting pressure relief valve and is usually expressed as a percentage of the DP/MAWP.

Generally there is confusion between the terms Accumulation and Overpressure. When we say ‘accumulation’, it means we are talking about the vessel, and when we say ‘overpressure’, we are talking about the pressure relief valve

Blowdown is the pressure difference between the set pressure and the pressure at which the valve reseats. It is usually expressed as % of the set pressure and refers to how much the pressure needs to drop before the valve reseats.

Reseat Pressure is the pressure at which the valve is fully closed.

The cold differential test pressure is the pressure at which the valve is adjusted to open on the test stand, and incorporates the effects of superimposed back pressure and operating temperatures

Pressure Relief Valve Sizing

Correct sizing of Relief Valves is crucial. If the relief valve is undersized it may not relieve sufficient quantity of fluid to prevent pressure build-up. This consequently may result in high pressure. If the relief device is oversized, the relief valve may become unstable during operation.

The sizing of a pressure relief valve is done by the Process team based on the governing codes and standards. The most widely used reference for pressure relief valve sizing is API 520. The parameters that affect the PRV sizing and selection are

  • Set the Pressure of the relief valve
  • Process Design temperature and pressure
  • Size of inlet and outlet piping
  • Backpressure on the pressure relief valve outlet
  • Fluid Service
  • The required capacity of the relief valve
  • Flow condition (liquid flow, gas flow (critical and sub-critical), steam flow, and two-phase flow)

The sizing of the pressure relief valve is a complex method requiring a multi-step process as listed below:

  • Defining the Protected System
  • Locating the relief valve
  • Defining the over-pressure condition
  • Selecting the relief device
  • Obtaining Data for Relief valve Sizing
  • Determining the flow condition types

The above steps can be easily shown in the form of a flowchart as shown in Fig. 6.

Pressure Relief valve Sizing Flowchart
Fig. 6: Pressure Relief valve Sizing Flowchart

Most major pressure relief valve manufacturers provide sizing software having the unlimited capability to accept wide variability of fluid properties and decide the right pressure relief valve. Some typical software for pressure relief valve sizing is developed by:

  • Anderson Greenwood Crosby
  • PRV2SIZE software Emerson Automation Solutions
  • PRV2SIZE software Pentair Software
  • VALVESTAR® by LESER Safety Valves
  • SIZEMASTER – Relief System Sizing Software by Farris
  • VALVIO by HEROSE
  • Fluid-Flow

In absence of pressure relief valve sizing software or manufacturer’s standard tables, the effective orifice area can be manually calculated using the following equations:

Pressure Relief Valve Sizing Equations
Fig. 7: Pressure Relief Valve Sizing Equations

After getting the effective area, the Standard pressure relief valve orifice designation (size) is selected from the following table:

Standard Orifice Designation for Pressure Relief Valve
Fig. 8: Standard Orifice Designation for Pressure Relief Valve

Pressure Relief Valve Symbols

Pressure relief valves are designated by special symbols as shown below:

Pressure Relief Valve Symbols
Fig. 9: Pressure Relief Valve Symbols

Fig. 9 also provides the P&ID representation of a typical Pressure Safety Valve. Set pressure and Orifice Designation is clearly mentioned in the P&ID, along with the identifier and symbol of the pressure relief valve.

Relief Valve Chattering

Chattering is the rapid opening and closing of a pressure relief valve at low flow rates. Under normal process conditions the vessel pressure is below the set pressure of the relief valve. As the pressure increases and exceeds the relief valve set pressure the valve opens. As soon as the valve opens there is flow resulting in a pressure drop between the vessel and the valve. If this pressure drop is large enough, the pressure at the relief valve can be low enough so that the relief valve closes. The flow stops, the pressure at the relief valve increases back to the vessel pressure because there is no flow to cause a pressure drop and the relief valve opens again.

  • Spring relief devices require 25-30% of maximum flow capacity to maintain the valve seat in the open position
  • Lower flows result in chattering, caused by rapid opening and closing of the valve disc
  • This can lead to the destruction of the device and a dangerous situation

Chatter – Principal Causes

Valve Issues

  • Oversized valve
  • Valve handling widely differing rates
  • Relief System Issues
    • Excessive inlet pressure drop
    • Excessive built-up backpressure

Oversized valves will partially lift at set pressure & then re-seat resulting in “chattering” of the disc which could damage the seat/disc surfaces and cause the relief valve to fail. It is good practice to install multiple relief valves for varying loads to minimize chattering on small discharges.

The general rule to prevent relief valve chattering: line pressure drop between equipment and inlet of RV during relief case must be <3% of RV set value.

Difference between a PSV and PRV

  • A Pressure Relief Valve (PRV) opens gradually in relation to the pressure, on the other hand when the pressure reaches a certain value a Pressure Safety Valve or PSV opens suddenly to release the overpressure.
  • PRV is normally used for liquid systems while PSV is for gaseous systems.
  • The set point of PRV is usually 10% above the working pressure while the set pressure in PSV is generally 3% above the working limit.

Online Courses on Pressure Relief Valve

If you still have doubts, undertake the specially designed below-mentioned courses to improve your understanding of the subject:

Few more useful Resources for you…

Pre-Commissioning and Commissioning Checklist for Flare Package
Flare systems: Major thrust points for stress analysis
Stress Analysis of PSV connected Piping Systems Using Caesar II
Articles related to Process Design
Piping Layout and Design Basics
Piping Stress Analysis Basics

Meaning and Requirements of ASME U Stamp on Pressure Vessels

Written by Anup Kumar Dey in Mechanical,Piping Design Basics

The ASME U Stamp is an indication of quality for Pressure Vessels. It ensures that the design, fabrication, inspection, and testing of pressure vessels conform to ASME’s guidelines. ASME U stamp is provided on the body or the nameplates of the pressure vessels as a certification to meet ASME requirements. Globally, more than 100 countries use the ASME BPVC code for the pressure vessel design and U-stamped vessels follow the requirements of ASME Sec VIII Div 1. For the maximum protection of life and property, ASME provides rigorous rules for Pressure vessels. In many countries, the government made it compulsory to purchase ASME U-stamped vessels.

Advantages of ASME U Stamp

The main advantages of the ASME U Stamp are listed below:

  • In many countries, for pressure vessel installations in human occupancy, the ASME U stamp is a must.
  • ASME U stamp is a mandatory requirement of most Insurance companies.
  • ASME U stamp is accepted under all jurisdictions.
  • Sometimes for approvals by local regulating agencies, the ASME U stamp is a requirement.

ASME U Stamp requirements

The pressure vessels under ASME U stamp requirements are specifically inspected by a third-party authorized inspector. The inspector must review and approve the calculations as well as witness the ASME hydro test. Such inspectors are commissioned by the National Board of Boiler and Pressure Vessel Inspectors. A complete data report is furnished in form U-1 containing the signature of the authorized inspector. The manufacturers of such pressure vessels need to be registered with the National Board for the production of ASME U-stamped pressure vessels. Also, they need to maintain a permanent data record of all pressure vessels.

The manufacturers wishing to qualify as ASME certified need to go through the following stringent safety procedures:

  • Preparation Stage: The manufacturer must fulfill all requirements, and fill all checklists.
  • Application stage: Submit the complete application along with a signed Accreditation and Certification Agreement Form and the required fee.
  • Assessment Stage: ASME review team will examine the design, manufacturing, inspection, and quality system of the applicant. Once the assessment is complete, the team will submit an evaluation report to the higher authority.
  • Certification Stage: Once the applicant successfully demonstrates the implementation of quality programs in every stage of vessel manufacturing, he is entitled to the ASME certification. Upon receipt of the accreditation, the manufacturer can stamp the ASME mark on the vessel’s surface or Nameplates. Fig. 1 below shows a sample ASME certification stamp template.
Sample ASME Certification Template
Fig. 1: Sample ASME Certification Template

For more details about the marking methods, nameplate details and data reports kindly refer to UG-118 to UG-120 from the latest edition of ASME BPVC Sec VIII Div. 1.

There is a timeline involved for each stage mentioned above. The following flow chart (Fig. 2) by the ASME provides a guideline for the same.

ASME Certification Timeline
Fig. 2: ASME Certification Timeline

Is ASME U stamping a mandatory requirement?

No, the U stamp is not a mandatory requirement. The requirement is decided by the client company. As pressure vessels operate in a wide variety of processes and environments, It is crucial to design and fabricate vessels of the highest possible standard and quality. ASME U stamp satisfies that requirement. Failure to obtain an ASME vessel can sometimes put the business at risk.

When do Pressure Vessels need Certification or U-Stamping?

Any vessel carrying pressure in excess of 15 PSI falls under the ASME Code and should be stamped or certified by the ASME. However, there are other factors as well.

How to find ASME Certified Companies in a country?

To find the list of ASME-certified companies kindly visit the following site: https://caconnect.asme.org/directory/?_ga=2.17247673.1842524440.1614010223-219895220.1614010223. Provide the country and certificate type and then click on the search button. It will list all the companies that have active ASME certification during that time.

Online Course on Pressure Vessels

If you wish to learn more about Pressure Vessels, their design, fabrication, installation, etc in depth, then the following online courses will surely help you:

Drip Legs: Definition, Purpose, Configuration, Selection, Installation, and Sizing

Written by Anup Kumar Dey in Engineering Materials,Mechanical,Piping Design Basics

What is a Drip Leg in Steam Piping?

Drip Legs are vertical piping pockets installed in steam piping to collect condensate. Installing drip legs in the proper location serves the purpose of a successful, water-hammer-free, system start-up.

Purpose of Drip Legs

Drip Legs are installed in steam mains to serve the following purposes:

  • Drip Legs are used for removing entrained moisture from the steam transmission and distribution lines to ensure high-quality steam for use in various plant applications, while also preventing damaging and dangerous water hammer.
  • As steam travels at high velocity through piping, moisture forms as the result of piping heat losses and/or improper boiler control resulting in condensate carryover.
  • Drip legs are therefore located at points where condensate may accumulate to allow for drainage by gravity down to a steam trap for proper discharge from the system. Since condensate drains by gravity, drip legs must be located on the bottom of the piping and designed with diameters large enough to promote the collection.

Drip Leg Installation guidelines

Due to heat loss and system start-up energy consumption, condensate is formed inside the steam pipes. For proper working of the steam system, this condensate must be drained by installing drip legs in main lines at appropriate locations.

  • Drip legs should be located at Vertical Lifts, Drops, or at the end of the steam line.
  • In the straight run of piping every 30 to 50 meters.
  • Installed directly ahead of the regulating or control valve, Manual Valves Closed for a Long Time.
  • Ahead of expansion joints or elbows.
  • Provide proper support (no sagging)
  • Provide slope towards Drip legs.

Drip Leg Categories

  • DRIP Applications: drip traps
  • PROCESS Applications: process traps
  • TRACING Applications: tracer traps. Steam tracing refers to using steam to indirectly elevate the temperature of a product using jacketed pipes or tubing filled with steam

Drip Leg Configuration

Because condensate drainage from steam systems is dependent upon gravity, the drip leg (Fig. 1) diameter is critical for optimum removal – larger is better.

Figure of a properly configured drip leg.
Fig. 1: Figure of a properly configured drip leg.

Fig. 2 below shows a typical loop used in a drip leg.

Typical Drip Leg Loops from Steam Mains
Fig. 2: Typical Drip Leg Loops from Steam Mains

Selection of Drip Leg Sizes

The selection of drip leg sizes for draining the main steam line depends on the types of warm-up methods as mentioned below:

  • Supervised Warm-up Method: Warming up of the power plant principal piping normally follows this method. Such lines are warmed up only once in a lifetime and hence long drip leg is not required.
  • Automatic Warm-Up Method: Such a warm-up method is used for frequent steam use leading to the requirement of bigger drip legs. A static head (dimension H in Fig. 2) is used in such cases.

Fig. 3 below provides the recommended Drip leg Sizes (Drip Leg Diameter and Leg Length) with respect to the main steam piping size.

Recommended Drip Leg Sizing
Fig. 3: Recommended Drip Leg Sizing

A carefully designed drip leg enables steam traps to effectively drain the condensate from steam mains. For that, the drip legs should be large enough to allow the condensate to drop out of the steam at the pipe bottom. Recommended drip leg sizing table (Fig. 3) provides a good reference for such a scenario. In case the drip leg is not sized properly, the condensate will blow along with the steam without separating out as shown in Fig. 4.

Effect of Drip Leg Sizing
Fig. 4: Effect of Drip Leg Sizing

Click here to know about Steam Traps: Steam Traps: Definition, Types, Selection, Features, Codes & Standards

H-beam vs I-beam: Major Differences | H-beam and I-beam Size Chart

Written by Anup Kumar Dey in Civil,Construction,Maintenance,Mechanical,Piping Interface

When it comes to structural engineering and construction, the choice of beam design plays a crucial role in ensuring the integrity and safety of a structure. Among the most common types of beams used are H-beams and I-beams. While they may seem similar at first glance, each type has its own set of characteristics, advantages, and applications.

H-beam or I-beam

Both H-beam and I-beams are structural steel materials used widely in the construction industry by civil engineering professionals. By a novice, both these members may seem to be similar. The horizontal elements of the I and H beam are known as flanges, while the vertical element is called as the “web”. The web resists shear forces, and the flanges are designed to resist most of the bending moment that the beam experiences.

In general, The design of both I-beam and H-beam is governed by any of the following criteria:

  • deflection: The target criteria should be to minimize deformation
  • vibration: the stiffness and mass should be decided based on vibration tendency.
  • bending failure by yielding
  • bending failure by lateral torsional buckling
  • bending failure by local buckling
  • local yield due to the high magnitude of concentrated loads.
  • shear failure
  • buckling or yielding of components

However, both are quite different from one another. In this article, We will explore the main differences between I-beam and H-beam.

What is an H-beam?

H-beam is an incredibly strong structural steel member. As the cross-section of this beam resembles the capital letter “H”, it is known as H-beam. Fig. 1 shows a typical example of an H-beam. The main characteristics of H-beams are:

  • Shape: The cross-section is symmetrical, providing uniform strength in all directions.
  • Dimensions: Available in various sizes, typically larger than I-beams.
  • Weight: Generally heavier than I-beams, which can affect transportation and handling.
H-beam Example
Fig. 1: H-beam Example

H-beams have an equal thickness in the two parallel flanges without any taper on the inside surface. Depending on the height and flange width; H-beams are classified into three categories. They are

  • Wide Flange Series H-beam
  • Medium Flange Series H-beam and
  • Narrow Flange Series H-beam.

H-beam Size Chart

Typical H-beam size and weight chart is provided in the table below: Refer to Fig. 2

H beam size and weight chart: Wide Flange Series (HW)

Grade

Size of the Section (in mm)

Cross-Sectional Area

Weight

Member Designation

 

H

B

t1

t2

r

cm2

kg/m

  

100 X 100

100

100

6

8

10

21.9

17.19

100x100x6x8

125 X 125

125

125

6.5

9

10

30.31

23.79

125x125x6.5×9

150 X 150

150

150

7

10

13

40.55

31.83

150x150x7x10

175 X 175

175

175

7.5

11

13

51.43

40.37

175x175x7.5×11

200 X 200

200

200

8

12

16

64.28

50.46

200x200x8x12

200

204

12

12

16

72.28

56.74

200x204x12x12

250 X 250

250

250

9

14

16

92.18

72.36

250x250x9x14
 

250

255

14

14

16

104.68

82.17

250x255x14x14

H beam size and weight chart: Medium Flange Series (HM)

150 X 100

148

100

6

9

13

27.25

21.39

148x100x6x9

200 X 150

194

150

6

9

16

39.76

31.21

194x150x6x9

250 X 175

244

175

7

11

16

56.24

44.15

244x175x7x11

300 X 200

294

200

8

12

20

73.03

57.33

294x200x8x12

H beam size and weight chart: Narrow Flange Series (HN)

175 X 90

175

90

5

8

10

23.21

18.22

175x90x5x8

200 X 100

198

99

4.5

7

13

23.59

18.52

198x99x4.5×7

200

100

5.5

8

13

27.57

21.64

200x100x5.5×8

250 X 125

248

124

5

8

13

32.89

25.82

248x124x5x8

250

125

6

9

13

37.87

29.73

250x125x6x9
H-beam Cross Section
Fig. 2: H-beam Cross Section (Reference for table dimensions)

What is an I-beam?

I-beams are also structural steel members but their cross sections resemble the capital letter “I”. Consisting of two flanges and one web, an I-beam has a slope on the inner surface of the flanges. Depending on the use, I-beam sections are available in a range of weights, flange widths, sections, depths, and web thicknesses. The major characteristics of I-beams are:

  • Shape: The cross-section is also symmetrical but generally has narrower flanges compared to H-beams.
  • Dimensions: Available in a range of sizes, often lighter than H-beams.
  • Weight: Typically less weight than H-beams, making them easier to handle in certain applications.

Fig. 3 below shows a typical example of I-beams.

I-beam example
Fig. 3: I-beam example

I-beam Size Chart

I-beam size charts for some common structural sections are provided below:

Designation

Dimensions

  
 

Depth
– H –
(mm)

 

Width
– B –
(mm)

 

Web Thickness
– d –
(mm)

 

Cross-Sectional Area
(cm2)

Weight
(kg/m)

  

UB 127 x 76 x 13

127

76

4

16.5

13

  

UB 152 x 89 x 16

152.4

88.7

4.5

20.3

16

  

UB 178 x 102 x 19

177.8

101.2

4.8

24.3

19

  

UB 203 x 102 x 23

203.2

101.8

5.4

29.4

23.1

  

UB 203 x 133 x 25

203.2

133.2

5.7

32

25.1

  

UB 203 x 133 x 30

206.8

133.9

6.4

38.2

30

  

UB 254 x 102 x 22

254

101.6

5.7

28

22

  

UB 254 x 102 x 25

257.2

101.9

6

32

25.2

  

UB 254 x 102 x 28

260.4

102.2

6.3

36.1

28.3

  

UB 254 x 146 x 31

251.4

146.1

6

39.7

31.1

  

UB 254 x 146 x 37

256

146.4

6.3

47.2

37

  

UB 254 x 146 x 43

259.6

147.3

7.2

54.8

43

  

UB 305 x 102 x 25

305.1

101.6

5.8

31.6

24.8

  

UB 305 x 102 x 28

308.7

101.8

6

35.9

28.2

  

UB 305 x 102 x 33

312.7

102.4

6.6

41.8

32.8

  

UB 305 x 127 x 37

304.4

123.4

7.1

47.2

37

  

UB 305 x 127 x 42

307.2

124.3

8

53.4

41.9

  

UB 305 x 127 x 48

311

125.3

9

61.2

48.1

  

UB 305 x 165 x 40

303.4

165

6

51.3

40.3

  

UB 305 x 165 x 46

306.6

165.7

6.7

58.8

46.1

  

UB 305 x 165 x 54

310.4

166.9

7.9

68.8

54

  

UB 356 x 127 x 33

349

125.4

6

42.1

33.1

  

UB 356 x 127 x 39

353.4

126

6.6

49.8

39.1

  

UB 356 x 171 x 45

351.4

171.1

7

57.3

45

  

UB 356 x 171 x 51

355

171.5

7.4

64.9

51

  

UB 356 x 171 x 57

358

172.2

8.1

72.6

57

  

UB 356 x 171 x 67

363.4

173.2

9.1

85.5

67.1

  

UB 406 x 140 x 39

398

141.8

6.4

49.7

39

  

UB 406 x 140 x 46

403.2

142.2

6.8

58.6

46

  

UB 406 x 178 x 54

402.6

177.7

7.7

69

54.1

  

UB 406 x 178 x 60

406.4

177.9

7.9

76.5

60.1

  

UB 406 x 178 x 67

409.4

178.8

8.8

85.5

67.1

  

UB 406 x 178 x 74

412.8

179.5

9.5

94.5

74.2

  

UB 457 x 152 x 52

449.8

152.4

7.6

66.6

52.3

  

UB 457 x 152 x 60

454.6

152.9

8.1

76.2

59.8

  

UB 457 x 152 x 67

458

153.8

9

85.6

67.2

  

UB 457 x 152 x 74

462

154.4

9.6

94.5

74.2

  

UB 457 x 152 x 82

465.8

155.3

10.5

104.5

82.1

  

UB 457 x 191 x 67

453.4

189.9

8.5

85.5

67.1

  

UB 457 x 191 x 74

457

190.4

9

94.6

74.3

  

UB 457 x 191 x 82

460

191.3

9.9

104.5

82

  

UB 457 x 191 x 89

463.4

191.9

10.5

113.8

89.3

  

UB 457 x 191 x 98

467.2

192.8

11.4

125.3

98.3

  

Common Beam Standards

Common standards that govern the shape and tolerances of structural beam sections are:

  • AISC Manual
  • IS 808
  • ASTM A6,
  • DIN 1025
  • BS 4-1
  • AS/NZS 3679.1
  • EN 10024
  • EN 10034
  • EN 10162

H-beam vs I-beam: Difference between H-beam and I-beam

H-beam vs I-beam: Dimensions and Weight

  • An H-beam has a significantly thicker web than an I-beam.
  • An I-beam normally has a slope of 1:6 to 1: 10 in the flange whereas the H-beam has a uniform flange.
  • An H-beam is heavier as compared to an I-beam.
  • The distance of the flanges can be widened as per requirement for an H-beam section but the same is fixed for the I-beam.
  • The moment of inertia is different for both beams.
  • In an I-beam, the size of the web is greater than the size of the flange whereas in an H-beam it may not be true.

H-beam vs I-beam: Mechanical Properties

  • The cross-section of the I-beam is poor against twisting as compared to H-beam.
  • In general, H-beams are more rigid and can carry more load as compared to I-beams.
  • H-beams are used as columns while I-beams are used as beams.

H-beam vs I-beam: Manufacturing

  • An I-beam is manufactured as a single piece throughout, but an H-beam is normally manufactured by welding 3 pieces of metal.
  • An H-beam can be produced to any desired size and height whereas the production of I-beams is limited by the milling machine capacity.

For easy comparison, the differences between H-beam and I-beam are provided in the following table.

FeatureH-BeamI-Beam
Cross-Section ShapeResembles the letter “H”Resembles the letter “I”
Flange WidthWider flanges than I-beams.Narrower flanges than H-beams.
Web DepthH-beams have deeper web.I-beams have shallower web.
WeightGenerally heavier than I-beams.Typically lighter than H-beams.
Load-Bearing CapacityH-beams possess higher load capacity.I-beams have lower load capacity.
StabilityH-beams have better lateral stability than I-beams.I-beams are more susceptible to buckling.
ApplicationsMajor application of H-beams are found in bridges, high-rise buildings, heavy machinery, etc.I-beams are widely used in residential, commercial, light industrial, etc.
CostH-beams are generally more expensive.I-beams are typically less expensive.
HandlingH-beams require more robust lifting equipment. So, they are difficult to handle.I-beams are comparatively easier to handle and transport.
VersatilityThey are suitable for heavy-duty applications.I-beams are the best for lighter loads.
DeflectionH-beams experience less deflection under load.Comparatively more deflection under heavy loads.
Connection TypesOften welded for continuous supportCan be bolted or welded
Table 1: H-beam vs I-beam

This table summarizes the key differences, making it easy to compare H-beams and I-beams at a glance.

In conclusion, both H-beams and I-beams have unique properties that make them suitable for different applications in construction and engineering. H-beams offer higher load-bearing capacity and stability, making them ideal for heavy-duty applications, while I-beams provide a lightweight, cost-effective solution for lighter loads. The choice between the two should be based on a thorough understanding of the specific requirements of a project, including load conditions, cost considerations, and structural integrity.

Frequently Asked Questions: H-beam and I-beam

1. What is the primary difference between H-beams and I-beams?

The primary difference lies in their cross-sectional shapes. H-beams have wider flanges and a deeper web, while I-beams have narrower flanges and a shallower web, affecting their load-bearing capacities and applications.

2. Which beam is stronger: H-beam or I-beam?

H-beams generally have a higher load-bearing capacity due to their wider flanges and deeper web, making them suitable for heavy-duty applications. I-beams are lighter and more suited for lighter loads.

3. In what applications are H-beams typically used?

H-beams are commonly used in bridges, high-rise buildings, and heavy machinery support where high strength and stability are required.

4. Where are I-beams commonly found?

I-beams are typically used in residential construction, commercial buildings, and lighter industrial applications, where the loads are lower.

5. How do the costs compare between H-beams and I-beams?

H-beams are generally more expensive due to the larger amount of material used, while I-beams are typically less expensive, making them a cost-effective option for lighter applications.

6. Are H-beams easier to install than I-beams?

I-beams are usually easier to handle and install due to their lighter weight. H-beams require more robust lifting equipment during installation.

7. Can both beam types be welded or bolted?

Yes, both H-beams and I-beams can be either welded or bolted, but the choice depends on the specific structural requirements and design considerations.

8. What factors should be considered when choosing between H-beams and I-beams?

Factors to consider include the type and magnitude of loads, span length, budget constraints, and the specific application requirements.

9. Do H-beams and I-beams have different deflection limits?

Yes, H-beams typically exhibit less deflection under load compared to I-beams, making them more suitable for applications where deflection limits are critical.

10. What are the maintenance requirements for H-beams and I-beams?

Both types of beams require regular inspections for signs of corrosion or damage. The maintenance needs will depend on the environment and exposure conditions, such as humidity and industrial pollutants.

What is a Needle Valve? Types, Symbols, Working

Written by Anup Kumar Dey in Engineering Materials,Mechanical,Piping Design Basics

In a piping system, There are a lot of ways to isolate the flow. Many types of valves and blinding systems are available for this. But the use and purpose of the Needle valves are very different. Needle valves are sometimes referred to as Plunger valves. This helps piping professionals to perfectly control and regulate fluid flow and pressure. The Needle valve got its name because of its narrow needle-like plug and port arrangement. The needle valves are small in size but fluid flow controlling is of exceptional accuracy.

Needle valves are linear motion valves, Which are used in instrument systems for throttling small volumes. A needle valve is a manual valve that is used where continuous throttling is required for flow regulation. Needle valves are somehow similar to globe valves in design with the biggest difference of sharp needle-like disks of this. The needle valve has an isolation system with very precise which is attended by the fine movement of the shaft, which enables the gearbox to move the piston tube in a sliding motion for opening and closing position. In this article, we will help you to understand the following:

  • What is a Needle valve?
  • Symbols and uses of Needle valves
  • Parts of Needle valves
  • Working Principle of Needle valve
  • Advantages and Disadvantages of Needle valves

What is a Needle Valve?

Needle valve
Fig. 1: Needle Valve

A needle valve is a type of valve that can be used to regulate or complete the isolation of the fluid. The unique feature of the valve is the structure of a small plunger with the shape of a Needle. The plunger features a small handle to operate the easy and precise operation of the valve. When fully attached, the extended end of the valve fits exactly into the seat, a part of the appliance that is being regulated. In case of the valve is opened by mistake, then also space between and needle and the seat is so less, that a minimal amount of substance will be allowed to pass through it.  

Needle Valve Symbol

Like Every pipe fitting and Special Item, the Needle valve has its own symbology system. Common Needle Valve Symbol is shown in Fig. 2.

NEEDLE VALVE SYMBOL
Fig. 2: Needle Valve Symbol

Parts of a Needle Valve

Needle valves consist of three major parts, the valve body and seat, the stem and stem tip, and the packing and bonnet. The stem incorporates fine threads to allow micrometer-like needle adjustment relative to the seat.

Needle valve parts
Fig. 3: Parts of a Needle Valve

Referring to the above image and corresponding marked serial numbers name of parts of the needle valve is as below:

  1. Valve handle
  2. Nut
  3. Bonnet
  4. Valve body
  5. Seat
  6. O-ring
  7. Packing
  8. Stem
  9. Handle screw

The needle valve body is normally made up of Brass, Bronze, Stainless Steel, or any other alloy materials. Valve seats are usually manufactured from PVC, CPVC, Plastic, PTFE, or Thermoplastic Materials.

Depending on the position of the needle, needle valves are available in three basic configurations.

  • as a simple screw-down valve (T-type needle valve)
  • oblique needle valve (angle pattern) that offers a more direct flow path, and
  • controlled outlet flow at a right angle to the main flow.

Needle valves normally provide Z- or L-shaped flow path through the body.

Application of Needle Valves

Wherever precise flow measurement is the required role of the needle valve comes into play. In comparison with a diaphragm valve, a Needle valve can handle more differential pressure.

Needle valves find their application in almost every industry wherever control or metering of steam, gas, oil, air, water, or other non-viscous liquids is needed. Needle valves are widely used in Power generation, Zoological sciences, Cooling, Instrumentation control, and Gas and liquid dispensation industries.

In slurries and viscous media, the needle valve is avoided as a small orifice can easily be blocked by thick material or solids.

Role of Needle Valves

The major roles that a needle valve performs are

  1. Flow control
  2. In pump start
  3. Pressure regulation
  4. Turbine by-pass
  5. Flow discharge
  6. Air regulation
  7. Reservoir inlet

Use of a Needle Valve

A needle valve finds its wide uses in the following applications:

  • All analog field instruments are installed with a needle valve to control the flow movement.
  • Needle valves help in situations where the flow needs to stop gradually.
  • The needle valve can be used as an on/off and throttle valve.
  • This can be used where metering applications are required such as steam, air, gas, oil, or water.
  • A needle valve is helpful with sample points in piping where a very little flow rate is required.
  • This valve can be used on gas bleeder lines.
  • Needle valves are used in automated combustion control systems in which accurate flow regulation is required.
  • It is used with constant pressure pump governors in order to reduce the fluctuation in the pump discharge

Types of Needle Valve

Depending on the operation style, three types of needle valves are available in the market. They are:

  • Manually operated threaded needle valve
  • Motorized Needle Valve: Use an electric or pneumatic actuator for operation.
  • Angle Needle Valve: Turn the output by 90 degrees instead of in-line.

Working Principle of Needle Valves

Needle valves can be operated either manually or automatically. Manually operated needle valves use a handwheel to open or close their disc. When Handle is turned in a clockwise direction its plunger lifts to open the valve and allow fluid to pass through. When the Handle is turned in an Anti-clockwise direction the plunger moves closer to the seat to decrease the flow rate and finally intercepts the flow of fluid.

Automated needle valves are connected to the hydraulic motor or an air actuator that helps to automatically open and close the valve. The motor or actuator will help to adjust the position of the plunger according to the timer or external data fed into the system, that is gathered during monitoring.

Both manually and automatically operated needle valves provide precise control of fluid flow rate. The handwheel is accurately threaded which means it takes multiple turns to adjust the position of the plunger from the seat. As a result, the needle valve can help better in regulation the flow rate in the system.

Needle Valve Design Standards

Frequently used needle valve design standards governing the valve design and selection are:

  • ASME B16.34
  • BS 7174 P4
  • MIL-V-24586
  • PIP PNDMV09N

Needle Valve Selection

The parameters that affect the selection of the right needle valve are

Advantages of Needle valve

The main advantages that a needle valve serves are

  1. With the help of this valve flow control at a very low rate with higher accuracy is possible.
  2. Needle valves are smaller in size. So, there is no issue of space during its installation.
  3. Throttling even with less volume of fluid is possible with this valve.
  4. Flow rates can be adjusted precisely.
  5. Its operation is easier.

Disadvantages of Needle valve

A few drawbacks of needle valves are

  1. There is a high-pressure loss in the needle valve because of the high restriction of fluid flow.
  2. They can be used only for low-flow rate piping systems.
  3. There can be damage to the seat and needle if the fluid has solid particles.
  4. It is not possible to say if it is in an open or closed position just by examining the handle position.
  5. Immediate opening or closing is not possible in these types of valves. Immediate operations can damage the seat of the need valve.

Ball Valve vs Needle Valve

The main differences between a ball valve and a needle valve are tabulated below:

Ball ValveNeedle valve
Ball valves use a Spherical ball for valve operationUses a needle to open and close the valve
Ball valves are Quarter turn ValveNeedle valves are Linear motion valve
Ball valves have Poor flow controlNeedle valves have precision flow control
Table: Ball Valve vs Needle Valve

About the Author

A major part of this article is written by Mr. Vaibhav Raj, a Piping Engineer by profession, currently working with a leading MNC as an Asst. Manager (Piping). To date, He successfully executed four Oil and Gas Projects in India with various clients Like EIL, RIL, SHELL, and RSPL. He is the lead author of the blog “ALL About PIPING“.

Types of Construction Equipment for Oil & Gas Projects

Written by Anup Kumar Dey in Civil,Construction,Mechanical,Pipeline,Piping Interface

Construction Equipment plays an important role in the construction process. Proper selection of equipment is necessary for the Economy, Quality, Safety, Speed, and Timely completion of the Project. A wide range of construction equipment is used in the construction industry to help to perform jobs in a smooth and easy way. Even though most construction equipment is quite common among industries, there could be the use of specialized construction equipment depending on the requirement. In this article, We will list down the name of construction equipment that is used frequently in Oil & Gas Projects. Fig. 1 below shows examples of typical construction equipment.

Types of Construction Equipment

Broadly, Construction Equipment is classified into the following groups:

  • Earth Moving equipment
  • Road making equipment
  • Hauling equipment
  • Piling equipment
  • Concrete Equipment
  • Quarry equipment
  • Pneumatic equipment
  • Lifting and handling equipment
  • Slip form equipment
  • Welding equipment
  • Shop Fabrication and Testing equipment
  • Pipe laying equipment
  • Construction equipment for electrical installation
  • Floating Equipment for marine works
  • Tunneling equipment
  • Other miscellaneous equipment

Earthmoving Equipment

Earthmoving equipment performs the task of digging and moving the earth. The name of construction equipment that falls under the earthmoving equipment category are:

  • Excavators/Hydraulic Excavators
  • Backhoe
  • Loaders
  • Bulldozers
  • Skid Steer Loaders
  • Trenchers
  • Motor Graders
  • Motor Scrapers
  • Crawler Loaders
  • Wheeled Loading Shovel/Wheel Loader
  • Vibratory Compactors
  • Trenchers
Names of Construction Equipment
Names of Construction Equipment

Road making equipment

As the name suggests, this equipment is used for making roads. Names of such construction equipment are

  • Road paver
  • Roller
  • Asphalt Concrete Plant

Hauling Equipment/Construction Vehicles

Names of construction equipment known as hauling equipment or construction vehicles are

  • Tractors Trailers
  • Trucks
  • Tippers
  • Dumpers
  • Tankers

Piling equipment

A list of construction equipment those help in piling works are

  • Piling Rigs
  • Rotary, Piling Rigs/Crane Mounted Rotary Piling Rigs
  • Piling Winch with Accessories
  • Pile Hammer
  • Boring Tools & Accessories for Piles of Different Diameters
  • Diaphragm Wall Rigs
  • Rectangular Grabs for Diaphragm Walls of Different Thickness
  • Tripod Type Bored Piling Equipment
  • Truck Mounted Direct Mud Circulation Type Bored Piling Rig
  • Vibratory Hammer
  • High-Pressure Mud Pump
  • Bentonite Mixing and Generating Unit

Concrete Equipment

This equipment help in concrete work and is very useful for constructing civil foundations. Examples of such equipment are

  • Batching Plants
  • Mixers
  • Concrete Pumps
  • Transit Mixers
  • Dumpers
  • Concrete Placers

Quarry Equipment

Normally, large and powerful machines are used in quarrying. Examples include

  • Crushers
  • Screening Plants

Pneumatic equipment

Common pneumatic equipment used in the construction industry are

  • Rock Drills
  • Compressors
  • Pavement Breakers

Lifting and handling equipment

The following lifting and handling equipment finds wide application in the construction industry

  • Cranes
  • Hoists/Winches
  • Heavy Lifting Tackles

Slip form equipment

  • Slip form Jacks
  • Hydraulic Pump
  • Tapering Slip Form

Welding equipment

Common welding equipment used in the construction industry are

  • Generators
  • Transformers
  • Rectifiers
  • Submerged Arc Welding Unit
  • Automatic Welding Set

Shop Fabrication and Testing equipment

  • Welding Machines
  • Bending Machines
  • Presses
  • Planers/Shapers
  • Milling Machines
  • Drilling Machines
  • Boring Machine
  • Lathe Machines
  • Cutting/Shearing/Slotting Machines
  • Threading/Rivetting Machines
  • Grinding Machines
  • Forging & Smithy
  • Material Holding Equipment
  • X-ray Unit
  • Gamma Ray Unit
  • Ultrasonic Weld Testing Unit
  • Dye Penetrant and Magnetic Particle Testing Unit
  • Hardness Tester (Vicker’s, Rockwell, or Brinell)
  • Brinell Hardness Testing Machine
  • Microscope for Brinnel Indentation
  • Rockwell Hardness Testing Machine
  • Pendulun Impact Tester for Charry & Izod Test
  • Hydraulic Press for Bend Test
  • Hydraulic Pressure Testing Machine

Pipe laying equipment

  • Backhoe
  • Side Boom
  • Road Boring Machine
  • Internal Lineup Clamp
  • External Line-up Clamp
  • Dozer
  • Track-wheel Mounted Cranes
  • Front end Wheel Loader Lowering Belts
  • Diesel Welding Sets
  • Compressor
  • Truck
  • Trailer
  • Dumper
  • Concrete Mixer
  • Pipe Bevelling Machine
  • Test Pump
  • Filling Pump
  • Dewatering Pump
  • Pressure Recorder
  • Temperature Recorder
  • Point Tester
  • Dead Weight Tester
  • Jack out Jig
  • Coating Machine
  • Holiday Detector
  • X-ray Machine with Crawler
  • Spud Barge
  • Tug
  • Barge
  • Crane with Clamp Shell
  • Diesel Power Generator
  • Winch
  • Submersible Dredging Pumps
  • Track Drill
  • Pipe Bending Machine
  • Motor Boat
  • Caravans

Construction equipment for electrical installation

  • Oil Filters
  • Relay Testing Kits
  • Hipot Kit
  • Transformer Ratio Test Kit
  • Oil Test Kit
  • Meggers
  • Earth Testers
  • Multimeters
  • Tong Testers

Floating Equipment for marine works

  • Jack up Platform
  • Cutter Suction Dredger
  • Grab Dredger
  • Submersible Dock Barge
  • Hydro clam Barge
  • Multipurpose Hopper Barge
  • Drilling & Blasting Pontoon
  • Crane Barge
  • Tug
  • Hatch Barge/Deck Barge
  • Dock Barge with Cement Batching Plant
  • Lifting Assembling Barge

Tunneling Equipment

  • Tunnel Boring Machine (TBM)
  • Road Headers

Other miscellaneous Construction Equipment

  • Dewatering Pumps
  • Blasting Gun
  • Guniting Equipment
  • Spray Gun
  • Airless Spray Gun
  • Elcometer
  • Distomat
  • Gunniting M/C
  • Theodolite
  • Drilling Rig for Soil Investigation
  • Personal Computer
  • Other special testing and calibration equipment/devices